OK Bill so what IS a mask? And how do you create it?

Giana: you are always so very helpful, many thanks. I do have Haxagon...

Y'all have to understand: I am reasonably sure many people, not just me have no idea how to do any on this, so very small steps, explanations and from the beginning definitions would go a long way. Probably why there aren't tutorials about this sort of thing around at all.